Topic explanation

Standard explanation

First evaluate the trig value, then select the principal angle with that value.

Key points

• Compositions outside principal ranges
• rule
• worked example
• Compositions outside principal ranges: First evaluate the trig value, then select the principal angle with that value.
• CONCEPT AND RULE: First evaluate the trig value, then select the principal angle with that value.
• METHOD: For compositions outside principal ranges, identify the given information and required result. Selec
• First evaluate the trig value, then select the principal angle with that value.
• Worked pattern: arccos(cos(4pi/3))=2pi/3.

Labelled diagram